There is a potential dangling pointer problem. we never clean
shadow_req, if there are multiple link lists in this series of
sqes, then the shadow_req will not reallocate, and continue to
use the last one. but in the previous, his memory has been
released, thus forming a dangling pointer. let's clean up him
and make sure that every new link list can reapply for a new
shadow_req.
Fixes: 4fe2c96315 ("io_uring: add support for link with drain")
Signed-off-by: Jackie Liu <liuyun01@xxxxxxxxxx>
---
fs/io_uring.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index b03630ced9ae..45ed66d17a64 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -2341,6 +2341,7 @@ static int io_submit_sqes(struct io_ring_ctx *ctx, struct sqe_submit *sqes,
if (!prev_was_link && link) {
io_queue_link_head(ctx, link, &link->submit, shadow_req);
link = NULL;
+ shadow_req = NULL;
}
prev_was_link = (sqes[i].sqe->flags & IOSQE_IO_LINK) != 0;
@@ -2524,6 +2525,7 @@ static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit)
if (!prev_was_link && link) {
io_queue_link_head(ctx, link, &link->submit, shadow_req);
link = NULL;
+ shadow_req = NULL;
}
prev_was_link = (s.sqe->flags & IOSQE_IO_LINK) != 0;
--
2.23.0
